Electsic-cttrrent controller



H. L. BRADLEY.

moms CURRENT CONTROLLER.

APPLiCATlON FILED I AY3. 1916.

lutontml Oct 7, i910.

5 SHEETS-*SHEET I Suva 1415014;

H. L. BRADLEY.

ELECTRIC CURRENT CONTROLLER.

APPLICATION FILED MAY 3. 19MB.

latem'ed OM. 7, 1912).

$2M, WM zhwmzza t1 ttomwvy),

H L. BRADLEY.

ELECTRIC CURRENT CONTROLLER.

APPLICATION mu) MAY 3. ma.

1 ,3 1 7,77 2. Patented on. 7, 1919.

5 SHEETS-SHEET 3.

H. L. BRADLEY. ELECTRIC CURRENT CONTRGLLER.

APPLICAHON F ILED MAY 3. l9l6.

Patented Oct. 7,1919.

5 SHEETS SHEET 4.

( yam xwwm dilemma H, L. BRADLEY. :LECTRIYC CURRENT CONTROLLER.APPLICATION FILED MAYS 191s.

1 ,3 1 7, 772. Patented Oct. 7, 1919.

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- O M $314 I. Z5 1 7 (6/6 8% wwwwm attomm m i o an a (chic .intifi ZiPRRY L. BRADLEY,

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F llIILVJAUKEE, "WISCONSIN.

ELECT3IC-GURRENT CONTROLLER.

Specification of Letters Patent.

"atented Oct. 7, 1919.

Application filed May 3, 1916. Serial No. 95.030.

To '55 whom. it may comer/'12 it known. that I, iiiuir L. linaneny. zen.oi the United titatcs. residing at. mire i. the county of irlilwaulaee.and .LQils'lli. have invented ccintin i ipii'overnents in Electricofwhich the follow- *ation. reference being bad to vying drawings-i,forming a part- "ehtes to improvement in ntroihng devices enrahie.contact resistance mediums disks or connninulitui mateance of saidmediums or memvaried h c pre sure. of the eiass in ihiited FitatesPatents No. dated March 32, 1.903. and is'o.

December 9, liii i. and in iiicatiot'i oi' iivndc ihadiev .tttf z',tiled January 22. nil-i. rue ion oi contiaiilers of the red to it. hasbeen c\i $i"(miil1' to arthe mechanism in such a manner that. .re wouldhe applied and released tnd oni x o i the resistance. medium aims. andas each plate 't'ormmg t oi the resistance medium. or.

oi coma "Hlitll materiai the whole is-aiwavr; in 'lrictmnal L1) 110....with the container or supporting means. the elements or nmterial nearestthe point at. which the pressure is applied will he sid'riectel to thegreatest variations in pr and these variations will decrease or theictional resistance to pressure changes will be increased as thedistance from the point of application o'l' pressure ineleas This isundesirable, as the elements or material subject to the greatest.pressure radiations are also suhjict. to the greatest variations ofcontact. resistance, and therefore pcr'lorm greater service in thenature of current control than their more passive neighhors, the resu ltbei ng that such elements or material are subjected to greater mechanical wear heat. andelectrical stress than the elements or materialatthe ends of the. resistance members remote from the. point. orappiiration oi pressure, and the temlcncv to deterioration from use isunbalanced, heing greater ah the pressurc-appl ving enti.

iihcm-stati". contrcilers of this tv in havin L i r eompr ihleresistanre members have been provided with frames and meciianismsupporting means of greater weight. and strength "than those generalhvemployed in the step h v step form of controllers having the wire coilor grid type oi resistance members. This has been necessary in order towithstand the mechanical stresses occurring when the mechanism wasoperated to compress the. resistance members. Lightuess and smalldin'iensions are of great importance .in many instances where this classof apparatus is used, for example, in the con trol of small portableelectric. hoists, air compressors. drills. grinders, etc.

For this reason the increased weight of the compression type oicontrollers is also undesirable.

The main objects of the present invention are, iirst. to provide meansby which pressure can be applied simultaneously at both ends ol' theresistance members. thus en abling the elements or material at bot-hends oi the nnrmhers to operate with maximum pressure va 'iations, andsecond. to so construct an electric. current controller oi this typethat the framework supporting the mechanism and resistance nnnnbers neednot:- be ot an greater weight and strength than that. used in connectionwith the wire coil and grid form of resistance. members.

in the accompaIrving drawings like, characters designate the same partsin the several figures.

Figure 1 is a side elevation of an electric current controller(anhodving the invention; Fig. 2 is a plan view oi. the same; Figl 3 isa longitmliual section on the line 3--3, Fig.

2. parts being broken away; Fig. 4 is a cross section on the line 4--4-,Figs. 1 and 2; Fig. 5 is av wiring diagram of the controller inconnection with an alternating currentin duction motor oi the squirrelcage type; and Fig. (3 is a similar diagram of the controller inconnection with a non-reversible direct current motor.

Referring to Figs. '1 to 4, il'ieiusive, showing the contrtnler in itsoff or normal state, the framework comprises a U-shaped metal plate ormain section 1. to which is at.- tachcd crosswise. tl'iereo't, aU-shaped hearing bracket. The bracket. 2 is provided with l :arings 3.in which a rock shaft. 4 is mounted. ilcccntrics 5 are mounted on theshaft 1 with their points of greatest eccentricit v on diametricallycmposite sides thereof. and are provided with eccentric straps 6, whichare connected by rods 8 with'eonalizcontacts 18, 19 and 20, to changethe re ationh p ot the phases of the current so as to reverse thedirection of rotation of the motor.

Turning the sheave 23 back in either direction to its normal or centralposition 0p crates first, to release the resistance elements or mediumfrom compression, and then to open the motor circuit at the contacts 19and 20 01' 19 and 20.

In connection with a non-reversible direct current. shunt motor as showninv Fig. 6, the resistance elements or medium are compressed in likemanner except in this case the sheave '23 with the eccentrics 5 alswitch drums 16 is turned in one direction I only trom its normal orcentral position.

By turning the sheave in a clockwise direction till initial engagementbetween the contact plate 17 and the contact 20 occurs, the circuit maybe traced beginning with the line 36 through contact in. contact plate1T. contact 20 and conductor 2-37 to the motor armature; thence throughconductor 3%, resistance members 12'. 12 and 12 to line 3 The fieldcircuit is traced 'from the line 37 through shunt field to. conductor41, conductor 42, to line 39:

As the sheave 23 with the eccentrics 5 and switch drums 16 is turnedfurther in a eloclnvise direction from its normal or cen tral position.the compression ot the resistance elements or medium of the members 1:2,12' and 12" is gradually increased and their resistance correspondinglylowered until the switch plate 17 brought into engagament with thecontact 1 there by short-circuiting the resistance members from theconductor 38 through conductor --3 contact 1!) contact plate 17. contact15% and conductor r). to line 235).

ii reverse movement ot the sheave J3 operates first. to open the shortcircuit at contact 1 then to relieve the resistance elements or mediumol' compression. and finally to open the motor circuit at the contact.20.

Various changes in details of construction and arrangement of parts ofthe controller may be made without departure from the principle andscope of the invention as de' fined n the following claims.

it "lilllili i in an rlcctric current controller the n oia compressibleresistance mint medium and means comprising oppositely movablecompression members for exerting pressure simultaneously in oppositedirections against both ends of the resistance medium. each compressionmember acting and reacting" against the other compression memberthroughout the entire length of said resistance medium.

2. in an electric current controller the combination ot a resistancemedium whose coiuluctivity is variable by compression and meanscomprising oppositely movable compression members tor subjecting saidmedium at opposite ends to variable pressure simultaneously in oppositedirections each. compression member acting and reacting against theopposing compression member throughout the entire length of theintervening resistance medium.

3. In an electric currentcontroller the combination of a compressibleand variable.

resistance medium composed of a series of disks. a casing supporting andloosely confining said disks, and means comprising oppositely movablecompression memlnrs t'or subjecting said medium simultaneously to. equaland variable pressure in opposite directions. each compression memberacting" and reacting: aeainst the opposing compression member throughoutthe entire series 0t disks.

4. In an electric current controller the combination ot a resistancemedium whose throughoutthe entire len th ot the resistance medium. andmeans connected with and operated by the compression means for openingand closing the circuit through the resistance medium.

5. in an clectric current cont-roller the combination ot a resistancemedium whose conductivity variable by compression, means comprisinpoppositely movable com pression members each acting against the otherthroughout the entire length of the intervening resistance mediilm torsubjecting: said medium simultaneously at opposite ends to equalpressures in opposite directions. and means connected with and operatedby the compression means to) shortcircuiting said medium at a certainstage of compression thcreol.

(3. ln an electric current controller the combination of a plurality o'tparallel coinpressible variable resistance members and means comprisingoppositely movable coinpression members tor subjecting said resi tancemembers simultaneously at both ends to equal aiul variable pressure inopposite directions each compression member acting

